1. Field of the Invention
The present invention relates to an automatic instrumentation system for automatic control of a plurality of instruments which are connected to a controller through some communication lines. In particular, the invention relates to an automatic instrumentation system for remote control of a plurality of instruments which are in locations far removed from the user. The present invention is based on a Japanese Patent Application, H9-9726 and a Japanese Patent Application, H9-202006, the contents of which are incorporated herein by reference.
2. Description of the Related Art
Conventional automatic instrument control is performed as follows. First, a plurality of instruments are connected to a controller using communication lines which are in compliance with a general purpose interface bus (GPIB) or RS-232C. Next, various control programs for on-line control of selected instruments are prepared. These control programs are written in programming languages such as Beginner's All-purpose Symbolic Instruction Code (BASIC) or by combining control commands particular to each instrument. Next, the controller executes the control programs to operate the selected instruments to perform automatic control of the on-line instruments.
However, to construct such automated instrument control systems requires that the designers (i.e. system engineers) be familiar with programming skills for these control programs. It means that not every one can readily construct an automatic instrumentation system.
Also, in the various control programs, those sections of the program that are delivered to the instrument to carry out the detailed steps of an instrument are made up of a combination of control commands. Each instrument has its unique ways of commanding which are different than the commands used for other instruments, and it is virtually impossible to standardize all command protocols among the different instruments. This is because the control commands for different instruments are different, depending on their end uses and capabilities. Therefore, a programmer must first become thoroughly familiar with explanatory booklets for various instruments to have a complete grasp of the control protocol for these instruments, and then to start developing a control program for the system. Therefore, even for a person of competent programming knowledge, preparation of control programs is not a simple task.
Furthermore, because each instrument responds to different control commands, even when a control program is developed for one particular instrument, it is difficult to adopt the same control program in an automated instrument control system based on another instruments. For this reason, when the configuration of the automated instrument control system is to be altered leading to a need for another control program, the existing control program requires reprogramming, and this requires almost as much effort as developing a brand new control program for the system.
To overcome such difficulties, a development of a set of softwares may be considered. The approach is to prepare a library of control programs in the form of dedicated modules which contain detailed steps for each instrument. By combining suitable sets of control program modules, an overall control program for the automated instrument control system can be developed.
In more detail, the programmer who is preparing a system control protocol preinstalls the library containing the control program modules and control softwares into the controller. In the stage of preparing an actual program for the overall system control, the programmer selects the control program modules for the selected instruments from the library and builds them into a main control program for the overall system.
By taking such an approach, the necessity for understanding the details of the control commands for each instrument can be eliminated so that all that is needed by a system programmer is a rudimentary knowledge of programming, and the effort required in developing a system control program can be significantly reduced.
However, the above approach requires that the program library must house many program modules pre-installed in the controller to provide for possible future connection to the controller. In other words, it becomes necessary to pre-install all the modules even for those instruments which are not now connected but had been connected at one time to the controller, or those which have a potential to be connected to the controller at some future date. This leads to the necessity of having a very large storage capacity for the controller, and the attendant high prices for the controller.
It is possible, of course, to reduce the memory needs by installing only those program modules which are necessary for the currently selected instruments, however, this approach is quite inconvenient because it is necessary to later install a control program module for each new additional instrument to be connected to the controller. Another possible scenario is that the original storage medium such as a Compact Disk Read Only Memory (CD-ROM) storing the control program modules has been lost, resulting that an old instrument cannot be connected and operated. In other cases, some instruments may have only recently been introduced to the marketplace or that they are special instruments which are applicable to limited lines of work For such instruments, there is no assurance that control program modules are available for every instrument. When such instruments are to be incorporated into a system, it is necessary that the system engineer himself must prepare control programs as though there are no control softwares available.